Puntuado con 1 de 5 estrellas

There does not seem to be a way to add new a new address to the drop-down. I just get my usual address. Not much new with that.

Esta valoración es de una versión anterior del complemento (3.2). 

Identity Chooser simply shows all addresses that you've setup in Thunderbird.

If you add a new account (or a new address to an existing account), Identity Chooser will pick it up automatically.